Electrical switching device



W. H. SHARPE. YELECTR-ICAL SWITCHING DEVlCE. APPLICATION FlLED MAY5.1920.

1,412,372. mema Apr. 11, 1922.

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. WM/'am h( 577476.

UNITED VSTATESV PATENT OFFICE.

winner/r' m sane, or nw-con, oHIo, ASSIGNOR ro WESTERN ELECTRIC com-FANS@ INCORPORATED, OF NEW YORK. N. Y.,A CoRPoRa'rIoNoF NEW YORK.

ELECTRICAL SWITCHING DEVICE,

S pecifieaton of Letters Patent. Patented A pr, 11, 1922,

Application file-&Ma 5, 1920. Serial. No. 3.78,972.

To all whom it 77104 cm'rccrn: i

Be it known that I, 'WILLIAM H. SHARPE, a citizen of the United Statesresding at Lakewood,-in the county of Cuyahoga State of Oho haveinvented certain new and useful Improvements in Electrical SwitchingDevices, of which the (following is a full clear, concise, and exactdescription;

This invention relates in general -to electrical switching devices andparticularly to switchingkeys of the plunger type.

The invention' `.is particularly` useful in connection With automatictelephone systems wherekeys ofthis typeare used `:for selecting trunklines attoll Stations. With the keys ordinarily in use` when depressed,

contacts are made which start; the selecting apparatus. If the key doesnot happen to lock and returns to its normal position the selectngapparatus halts without completin'g the proper connection.

The object of the invention :is to provide a group of keys, positive inaction and simple in Construction.

To accomplish this object the invention in its preterred form provides alooking plunger type key which does not close its correlated Contactsuntil it is locked in its depressed position. Another plunger key isprovided whose contacts do not make until depressed to aposition whereit operates to release the other key.

With this arrangemenh the person operating the keys is certain that thekeys have performed their proper function.

The invention is shown in its preferred form in the drawing, in whichFig. 1 is a side View with portions of the looking apparatus cut away toshow the Construction thereof, and Fig. 2 shows a cross-sectional Viewat the plane 2.

A supporting plate 1, having a bent up edge 3, is provided withapertures 29 and is fastened in any suitable manner to the underside ofa shelf 4:. Plunger-rods 5 and 6 are adapted to move through theapertures spectively by means of screws 14:.

A cylindrical cam 17 is fastened on the shank of the .plunger 5 andooperates with a roller 19 supported crosswise oi* the locking member12. A conieal cam 18 supported on the shank of the plunger 6 cooperateswith 'a roller 20 supported crosswise oi' the looking member 12. Astrip2l of slightly elastic material is fastened 'between the came 17and 18 and the edge 3 to 'absorb the shock when the cams 17 and 18 ares'uddenly released. f i

A stifl' contact spring member 22 mounted on the supporting plate 1 bymeans of a fiange 24 is adapted to bear against a roller 30 which issupported crosswise of the locking member 12 and tends to pull'tlierollcrs 19 and 20 against the cams 17 and 18 re- A contact member 23 isprovided to engage'the spring member 22 when released and is suitablysupported with the spring member 22 on the fiange 24. A bank of springs25 may be'supported on the flange 26 of the guide member 9 and may beoperated in the usual manner by a conical cam 27. The key' buttons 28,of any suitable form may be fastened to the tops of the plungers 5 and 6tor the purpose of depressing the same.

When the plunger is depressed, the top of the cam 17 drops below theroller 19. The looking member 12, under the influence of the springmember 22, then slides to the right and the roller 19 locks the plunger5 in its depressed position. Contacts 22 and 23 then engage to close anelectrical circuit. To release the plunger 5, plunger 6 is depressed andthe conical cam 18 forces the roller 20 to move the looking member 12 tothe left whereupon the cam 17 being released, the plunger 5 rises to itsnormal position. Simultaneously, the spring contact members 25' contact,under the influence of the cam 27 and the contact between springs 22 and23 is broken.

What is claimed is:

1. In a key assembly, a plurality of manually operable members, lookingmeans for one of saidmembers, means associated with sad member toprevent the operation of said looking means When said member is notoperated, means associa'ted With another of said members to restore thelooking means, and circuit controlling means operable by the lookingmeans.

2. In a key assembly a plurality of pluuger keys, looking means means tooperate said looking means, means associated With one plunger key toprevent the operation ot said .looking means when the plunger key is notdepressed, means .associated With another plunger key to restore thelooking means, and circuit c0ntr'lling means oper able by the lookingmeans.

3. In a key assembly a looking plunger key, a non-looking plunger keylooking means :for the locking`plunger key restoring means operated bysaid non-looking key to release said looking means, contact membersoperable by said looking means, and means associated With the lookingplunger key normally preventng the operation ol" the contact members bysaid looking means.

4-. In a key assembly, a plurality of plunger rods, an end-wise slidablelooking member, a spring contact member tending to produce a slidingmotion in the said locking member, a cylindrical eam supported on ne ofsaid plunger rods preventing such slidng motion When the plunger is notdepressed a conical cam supported by another of said plunger rods toreturn the looking member to its normal position and a contact member tocontact With the said spring contact member.

In a key assembly, a plurality ol" pluuger rods, an end-wise slidablelooking member cooperative therewth, a spring contact member to operatesaid looking member a cylindrical cam fastened on one of the said plu.-gers and adapted to release the said looking member and lock the saidplunger in a depressed position, and a conical cam lastened on anotherof said plungers to return the said looking member to its normalposition.

6. In a key assembly, a supporting plate of L shaped cross-sectio',provided with apertures, a pair of plunger rods slidablc through suchapertures, a guide member for each said plungerod and supported by thesupporting plate, a cylindrcal cam *lastenerl on one of said plunger'ods, a conical cam :l'astened on the other of said plunger rods coilsprings on the plunger rods tending to keep the rods in an elevatedposition, a locking member of U shaped cross-section slidahly supportedon the suporting plate and having portions cut away to pernit thepassage of the flunger rods therethrogh, roller members su1')ported bythe U shaped looking member and cooperative With the said cams, a springcontact member tending to press the roller members against the saidcams, and contact means for said spring member.

In witness Whereof, I hereunto subscribe my name this 23rd day of Aprl,A. D., 1920.

W. H. SHARPE.

